16 



Molecular Action of Ionizing 

 Radiations 



I. Introduction 



The effects of ionizing radiation on living matter can be considered at 

 many different levels. The most complex is that of the entire animal or 

 plant. Exposure of entire organisms to ionizing radiation may result, 

 depending on the dose, in induction of cancers and mutations, radiation 

 sickness, and even death. Although health physicists must learn what 

 these complex responses are and at what dosages they are likely to occur, 

 the complexity prohibits complete understanding at this time. Even- 

 tually, it is believed that the responses of higher animals and plants to 

 ionizing radiation will be explained in terms of effects occurring at the 

 cellular level. The latter have been discussed in Chapter 10. Particular 

 stress was given to changes induced in the chromosomes. The cellular 

 effects of ionizing radiations can be explained in part in terms of molec- 

 ular changes. The current chapter emphasizes the effects on the 

 molecular level, and in particular on the natural high polymers. Further 

 logical extensions of this process of abstraction would be to consider the 

 interactions of ionizing radiations with small molecules, atoms, and 



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